Language: French with English summary
A flora treatment of the Costaceae family in the Democratic Republic of the Congo, Rwanda and Burundi is given. In this region, the family is represented by a single genus, Costus, of which six species occur. The genus is well represented in the Democratic Republic of the Congo, but very few collections are known from Burundi and none from Rwanda. Most species of Costus occur in various types of rain forest vegetation, but one is a typical savanna species (the acaulescent C. spectabilis). By far the most common species is C. phyllocephalus. Three species occurring in neighbouring countries, but which are expected to occur in the Flora region as well (C. fenestralis, C. ligularis, and C. tappenbeckianus) are included in the key. A key to all species is provided, as well as full morphological descriptions including synonymy and data about distribution, habitat, uses and vernacular names.